A common method for recovering metal values from ores containing the same includes leaching the ores with an acid. The acid solubilizes the metal values. The acid leach solution so obtained, then is processed for recovery of the metals contained therein.
Another common method of recovering metal values from ores is by chlorination of the ore in a fluid-bed reactor. Titaniferous ores such as rutile and ilmenite are chlorinated to produce titanium tetrachloride which, subsequently, is processed to produce either titanium metal or pigmentary titanium dioxide. When the chlorination is effected in a fluid-bed reactor, a substantial quantity of solids are carried out of the reactor by the effluent gases generated therein. A substantial portion of the solids comprise carbon and unreacted ore. The solids also include, however, significant amounts of anhydrous chlorides of such metals as vanadium, niobium, titanium, chromium, zirconium, aluminum and iron. In most plant operations, the solids are separated from the gas stream and quenched in water to pacify the highly reative anhydrous metal chlorides contained therein, thus, producing an aqueous solution of hydrochloric acid containing the aforementioned metal values.
Separation and recovery of metal values such as niobium and vanadium from a hydrochloric acid solution is difficult. More particularly, most metal recovery processes, applicable to hydrochloric acid solutions, remove both metals simultaneously.
Obviously, an economical method of selectively recovering metal values from a hydrochloric acid solution is desirable.